The disclosure relates to a hydrostatic drive which is provided in particular for starting an internal combustion engine, in particular a diesel engine.
WO 2012/125798 A1 has disclosed a hydrostatic drive which has a hydraulic machine which, during operation as a hydraulic motor, can start an internal combustion engine, and during operation as a pump, can charge a hydropneumatic high-pressure accumulator and supply pressure medium to further hydraulic consumers.
The hydraulic machine is adjustable in terms of its swept volume from a maximum positive swept volume via a swept volume of zero to a maximum negative swept volume by means of a hydraulic adjustment device, wherein pump operation is possible in the case of a positive swept volume and motor operation is possible in the case of negative swept volume. Here, the swept volume is the quantity of pressure medium that is delivered or taken in by the hydraulic machine per revolution of a driveshaft. The hydraulic machine can, for operation as a hydraulic motor, be supplied with pressure medium via a pressure line which runs between a pressure port of the hydraulic machine and the high-pressure accumulator. An accumulator shut-off valve with a first position and a second position is arranged in the pressure line, wherein a fluidic connection from the high-pressure accumulator to the hydraulic machine is open in the first position and is shut off in the second position. The accumulator shut-off valve is actuable as a function of the signals of an electronic control unit.
A hydraulic adjustment device for the swept volume of a hydrostatic machine conventionally has one or more adjustment pistons, which are adjoined by adjustment chambers, and at least one restoring spring, under the action of which the hydraulic machine is set to a predetermined swept volume when a pressurization of the adjustment chambers is ended.
The disclosure is based on the object of providing a hydrostatic drive for starting an internal combustion engine, in the case of which the hydraulic machine can be adjusted out of the adjustment range with a negative swept volume quickly and without excessive load being placed on the components.